Yeah, the new blower is gonna set you back about $7,500, so you're pretty close in your estimates.....but exactly what do you think you'll have to sink into an SN95 (or any previous Mustang for that matter) in order to see the same reliable, pump gas friendly 625hp like you would the new 5.0L?
Answer....at least double if not triple that. I personally like the idea of a hassle free, single bolt on item making 10-second power levels. No guess work and minimal down time. While previous generation Mustang owners are slowly sucking their wallets dry, busting their knuckles and banging their heads trying to reliably create these type of power levels, I'd be out enjoying my new 600+hp car.
Now...if turning wrenches and adding parts over time to accomplish your goal your thing, nobody will fault you. But just know that in the end...it'll end up costing you more money/time to do so....not less.
If you're talking about 98COBRA281, then most certainly his car will outrunning a
stock '11 GT in a straight line.....but hand it to one in the twisties...doubtful. Especially with the slicks/skinnies, drag
suspension and rear sway bar removed the way it was set up when he ran his 12.0 time slips.
Then ask him what kind of mileage he's getting, how his drivability and ride quality have faired and what his most recent emissions test results were? While we're at it, see what his bumper to bumper warranty coverage is like on top of that.
It's all about compromises my friend. Some people are willing to make them in the name of excellent performance and some don't have to.
His car is purpose built, with one goal in mind....to go fast in a straight line and look/sound cool doing it. But don't kid yourself.....even he'll tell you that it that point its hardly suitable as a daily driver.
I'll also bet he's got quite a penny sunk into that car with all of the changes he's made to it over the years. When you take into consideration the cost of the car on top of it all, I'd bet "money spent" is not far off what you'd pay to drive an '11 GT off the lot. Lucky for him he's mechanically inclined and was able to do a lot of the work himself. I'd hate to think what labour cost would have been were they factored into the total cost. Wanna take bets as to which of the two cars would have cost him more money in the end.